Such a front jaw is described in Austrian Pat. No. 315,698. The basic purpose of this known construction was to produce a simple construction and space-saving design. This is clearly achieved by the known solution. A disadvantage of the known construction lies, however, in the spring force being dependent on the conditions of the engaging points of the lever arms on the jaw parts. Therefore, the purpose of the present invention is to produce a solution through which the spring force can be reduced.
The designated purpose is attained inventively by the two-arm levers engaging with their area facing the jaw a support plate which is loaded by the spring acting onto the locking member.
This measure permits the spring force to be reduced to approximately 70% of the actual value thereof. In extreme cases, the spring force may even be reduced to 50%, however, then a large width of the front jaw must be accepted.
A particularly preferred embodiment of the invention is seen in the support plate being supported by means of a guideway on a fixed part of the jaw, for example on the outer surface of the setscrew for adjusting the spring force. In this manner the spring force is reduced to a value of 50% without any excessive increase of the binding width. This value can still further be reduced, if according to a further characteristic of the invention, the surface on which the support plate is supported is made of a material having particularly favorable friction characteristics. In this case, the jaw is independent of dirt and pure spring forces can be used for calculating the release force.
The invention also relates to a front jaw having a ski-fixed base plate on which two pivot axes are arranged perpendicularly with respect to the base plate, each pivot axis having pivotally supported thereon a two-arm lever, whereby the longer lever arms engage the ski boot, the shorter ones, however, being associated with a locking member which is movably guided in the longitudinal direction of the ski against the force of a spring. The locking member is constructed as a pull rod which has in the area of the end which faces the two-arm levers an annular groove or two hooks into which engage the shorter lever arms (or intermediate levers supported on said lever arms). Each two-arm lever has at its common area, which does not face the associated pivot axis, an anchor member having a control linkage which is connected or can be connected through its other end to a support frame. The support frame is guided parallel to the pull rod on a fixed part of the jaw, for example on the outer surface of the setscrew for adjusting the spring force. In this manner, the spring force can be reduced as desired, so that a limit is determined only by economical consideration. One can rely for a practical use on spring forces of approximately 10% to 20%.
In a further development of this inventive thought it is possible to releasably connect the control linkage with the support for example through a holding bracket on the support frame, whereby the individual holding brackets have holes therein for receiving connecting pins, bolts, screws or the like to couple the free ends of the control linkages to the brackets.